Responsible for the deacetylation of lysine residues on the N-terminal part of the core histones (H2A, H2B, H3 and H4). Histone deacetylation gives a tag for epigenetic repression and plays an important role in transcriptional regulation, cell cycle progression and developmental events. Histone deacetylases act via the formation of large multiprotein complexes. Involved in muscle maturation by repressing transcription of myocyte enhancer factors such as MEF2A, MEF2B and MEF2C. During muscle differentiation, it shuttles into the cytoplasm, allowing the expression of myocyte enhancer factors. May be involved in Epstein-Barr virus (EBV) latency, possibly by repressing the viral BZLF1 gene. Interacts with HDAC1, HDAC2, HDAC3, HDAC4, HDAC5, NCOR1, NCOR2, SIN3A, SIN3B, RBBP4, RBBP7, MTA1L1, SAP30 and MBD3. Interacts with the 14-3-3 protein YWHAE, MEF2A, MEF2B and MEF2C. Interacts with KAT5 and EDNRA. Interacts with KDM5B. Interacts with ZMYND15. Belongs to the histone deacetylase family. HD type 2 subfamily. 10 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.